The present invention relates to electrophotographic marking machines, and more particularly, to the testing of subsystems of the electrophotographic process and to provide for specific subsystem adjustment procedures in relation to predetermined parameters.
The electrophotographic marking process is relatively complicated and employs a plurality of subsystems, each of which must be properly functioning. However, as these subprocesses are inter-related, it is often hard to diagnose and isolate the function of a particular subsystem. This is particularly critical for electrophotographic image formation and image development processes as visual inspection under ambient light is typically impractical.
Therefore, the need exists for the analysis and diagnostic testing of an electrophotographic process wherein specific subsystems may be compared to acceptable operating parameters and appropriate remedial actions taken.
The present invention provides the selective control of an electrophotographic marking machine to allow the functional testing of subsystems. In a further configuration, the invention provides for each subsystem functional test to be self-executing and thus compliment subsystem specific diagnostic and checkout programs.
Thus, the present invention provides for the creation of a reference voltage on a photo conductive member such as a belt, wherein the belt is rotated in a non-print mode to be exposed to a predetermined subsystem and the resulting voltage is measured and compared to predetermined acceptable limits. Subsequently, a recovery cycle is implemented to place the electrophotographic marking machine in a print mode.